Of all the following malignant skin cancers, which one is the most common?

A. Actinic keratosis: Actinic keratosis is not a malignant skin cancer but rather a precancerous lesion caused by chronic sun exposure. While common in older adults, it has the potential to progress to squamous cell carcinoma if untreated. B. Melanoma: Melanoma is the most dangerous form of skin cancer due to its high potential for metastasis and mortality. However, it is less common compared to basal cell carcinoma and squamous cell carcinoma, accounting for a smaller percentage of skin cancer cases. C. Basal cell carcinoma: Basal cell carcinoma is the most common type of malignant skin cancer, representing the majority of skin cancer diagnoses. It grows slowly, rarely metastasizes, but can cause significant local tissue destruction if not treated promptly. D. Squamous cell carcinoma: Squamous cell carcinoma is the second most common skin cancer after basal cell carcinoma. It has a higher metastatic potential than basal cell carcinoma but is still less frequent in occurrence.